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Thread: Lear 35 down approaching Teterboro

  1. #41
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    ... thanks to a couple of well-timed feats of cowboy ejectmanship!
    Be alert! America needs more lerts.

    Eric Law

  2. #42
    Senior Member LH-B744's Avatar
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    Quote Originally Posted by Gabriel View Post
    130 kts is 67 m/s.
    At 90 deg of bank you will not hold the altitude or attitude no matter how much you "pull up" (because "up" is 100% horizontal), but that doesn't prevent you from making the turn, and all the lift will contribute to the radial acceleration needed to bend the speed vector (i.e. turn).
    So let's say that you pull with a load factor of 2.5, that means that the lift will be 2.5 times the weight, and since the lift will be the only horizontal force with a radial component (neglecting an radial component that the thrust may have), we have

    Sum of F radial = 2.5 x weight = m x acc radial
    Since weight = m x g (g = acceleration of the gravity =~ 10 m/s2)
    2.5 x m x g = m x a
    So, a = 2.5 g = 25 m/s2

    Now, in a circular motion, a = V2/r, so r = V2/a = (67 m/s)2 / 25 m/s2 = 179 m = 0.1 NM

    How much with a 30 deg bank turn, assuming we hold the vertical speed constant?

    Well, the vertical component of the lift needs to be equal to the weight.
    The lift vector, tilted 30 degrees from the vertical, will need to measure weight / cos 30 deg.

    1/cos 30 = 1.15 will be the load factor (and, if you are interested, the stall speed will be sqrt(1.15) = 1.075 times, or 7.5% faster than, the 1G stall speed). But we are not interested in anything of this.

    The horizontal component of the lift, the one that will make the plane turn, will be lift x sin 30, and since lift was = weight / cos 30, we get that the horizontal component will be weight / cos 30 x sin 30 and that's weight x tan 30 = 0.58 times weight (and remember that weight = m x g).

    Horizontal force = horizontal component of the lift = 0.58 x m x g = m x a
    a = 0.58 g

    a = v2/r

    r = v2/a = (67 m/s)2 / 0.58x10 m/s2 = 773 m or 0.42 NM

    At 15 deg bank it would be 0.9 NM.
    Now I know where all of you "Senior members" got their 6,000 or 8,000 entries from... You always look when "the young boys" like me are not online, and then you ask your neighbor, who must be a mathematics professor, to write 300 or 900 entries...

    Gabriel, but you don't wanna tell me that you do all this inflight, with only 1 of 2 engines, or only 2 of 4 engines running.

    Flight Captain Chesley Sullenberger in his Airbus A320 is a hero in my eyes. Sullenberger deserves a golden star with a diamond because his decision is unique, until today. And why?
    Because he knew what his a/c is able to do, in a jet with ZERO engines running. And he still knows how to get the best results in an A320. Evidence? "Sully The Film" (2016), where Sullenberger as senior advisor and reason for the film appeared at the end.

    I don't think that he safely could've transformed his jet into a ship if he used 208 seconds for calculation. In German, it is called - it is late enough isn't it - Arschgefühl. You either have it for a special a/c type, or not.
    Last edited by LH-B744; 06-04-2017 at 05:17 AM. Reason: Thank God, I have never sat in a jet with zero engines.
    One evening, not long ago, I watched TV and I wondered what you will possibly do after you've lost one parent. Strange question, why did I wonder. You will possibly be annoyed because he will miss so many happenings which you liked to show him. But after you somehow have regained your countenance, you will also join again people who you don't know. Stay strong, Jimmy.

    Aviation enthusiast since more than 30 years.

  3. #43
    Senior Member LH-B744's Avatar
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    Argentina really mentions bank angles between 30 and 90°? Is this the first time when I doubt who at least once in his life has sat in a
    CR7 (Bombardier Canadair Regional Jet 700) simulator?

    I only mention it because imho, one of the very few civilian jets that have to be handled with more care than a CR7 is a Lear Jet, and in this case the Keyword is "smaller engines would still be big enough".

    Why do you think, that, engineers, on the basis of the CR7, were only be able to develop the CR9, with exactly the same engine type?

    Only because the CR7, with 20 seats less than the CR9, had too much horse power.

    Since I am here, it is the same topic. I'd never buy a BMW limousine with more than 900 hp, or a 1978 VW Beetle with more than 350 hp.

    If you have too much power, not the bank angle is your problem but your response time. In 2017, I haven't mentioned yet a story that happened when I became a JP member. So, here it is again.
    4 young boys somewhere in the USA, the oldest only less than half as old as me (19?), tried to drive father's BMW M5, and they discovered a private airstrip with a hill at the end of the strip. The end of the story was, car parts and body parts that hung down from trees.

    We still don't know the age of the two dead pilots in the Lear 35, or do we?

    Leichtsinn und Übermut ist (meistens) eine Jugendsünde, but that's only my assumption.
    One evening, not long ago, I watched TV and I wondered what you will possibly do after you've lost one parent. Strange question, why did I wonder. You will possibly be annoyed because he will miss so many happenings which you liked to show him. But after you somehow have regained your countenance, you will also join again people who you don't know. Stay strong, Jimmy.

    Aviation enthusiast since more than 30 years.

  4. #44
    Senior Member LH-B744's Avatar
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    If I'm allowed to only add one very short comparison. Sometimes, my feeling about "too much power" is not only a feeling...

    in anticlimactic order:

    Lear 35: 2x 18 kN = 8 t ... thats a ratio of almost 5:1

    Falcon F-16 (inaugurated 1978_): 1x 76 = 19 t ... that's a ratio of exactly 4:1, of course without afterburner.

    Cr7: 2x 61 = 34 t ... thats a ratio of less than 4:1

    ... ...
    So, it seems as if Lear 35 pilots should be better educated than F-16 fighter pilots! Ejection seats included.

    And I thought, the CR7 is quite powerful..
    Last edited by LH-B744; 06-04-2017 at 07:08 AM. Reason: Until my first JP decade, I'll learn this 8_)
    One evening, not long ago, I watched TV and I wondered what you will possibly do after you've lost one parent. Strange question, why did I wonder. You will possibly be annoyed because he will miss so many happenings which you liked to show him. But after you somehow have regained your countenance, you will also join again people who you don't know. Stay strong, Jimmy.

    Aviation enthusiast since more than 30 years.

  5. #45
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by LH-B744 View Post
    Gabriel, but you don't wanna tell me that you do all this inflight, with only 1 of 2 engines, or only 2 of 4 engines running.
    I totally agree. You need to do this stuff before flight. I mean, not do all the math I did, but you need to have a feeling of how much room you need to turn, how much you can safely bank at a given airspeed, etc...

    And, most important, you shall not exceed your airplanes's and your personal limitations. If, in the middle of the flight where you cannot do all this math, you find that a normal turn is not enough to align with the runway, you don't tighten the turn, you go around. That's the equivalent of the pause button in the flight simulator. It gives you time to stay off trouble and evaluate your options.

    And I don't know where you got that not all engines were running...

    Flight Captain Chesley Sullenberger in his Airbus A320 is a hero in my eyes. Sullenberger deserves a golden star with a diamond because his decision is unique, until today. And why?
    Because he knew what his a/c is able to do, in a jet with ZERO engines running. And he still knows how to get the best results in an A320. Evidence
    Well, captain Chesley Sullenberg is my hero exactly for the opposite reason. He DID NOT know what plane was able to fo. He DID NOT know if he could reach La Guardia or Teterboro. In the aftermath, those 2 airports were marginally within gliding reach. But he DID NOT know that up there. So he is my hero because, having a couple of airports that maybe he could reach, he decided not to risk it and go for an outcome that was bad but was safer than what may have happened if he tried to reach an airport and failed. It is very tough for a pilot to take a decision to land off airport, in the water, knowing that there may be deaths, when you know that there are airports that MAYBE are within reach. But he still did it. He went for what he knew, even when it was bad, instead of going for a story with an open ending. And for that he is my hero.

    As he said: "The Hudson was the only surface wide enough, long enough and smooth enough that I KNEW where within reach". The most important part of that statement is "I KNEW". If the investigation had demonstrated that La Guardia or Teterboro were not that marginal and were reasonably easy to reach, that would not have change my view of him. Up there and facing this hard decision, he didn't know what the investigation would reveal latter and he didn't have the means, tools or time to make that calculation himself.

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
    --- Defend what you say with arguments, not by imposing your credentials ---

  6. #46
    Senior Member Evan's Avatar
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    Quote Originally Posted by LH-B744 View Post
    Flight Captain Chesley Sullenberger in his Airbus A320 is a hero in my eyes. Sullenberger deserves a golden star with a diamond because his decision is unique, until today. And why?
    Because he knew what his a/c is able to do, in a jet with ZERO engines running.
    If I may split a hair here, Sully had both engines running the entire time. They were just too damaged to produce any useful thrust. It seems like a redundant point from a thrust perspective, but from a systems perspective it made a big difference. The LPC spools continued to turn and combustion was not affected. This allowed vital accessories driving hydraulics to remain functional. Sully could have seen this on the engine display as he reported to ATC that he had "lost thrust in both engines". The engine restart efforts were futile because of the combustors were still running, but the crew could not have been expected to assess this in the time they had to react.

  7. #47
    Senior Member Evan's Avatar
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    Quote Originally Posted by LH-B744 View Post
    NEvidence? "Sully The Film" (2016), where Sullenberger as senior advisor and reason for the film appeared at the end.
    BTW, I imagine Sully must have blushed when he saw the final film CGI effect. Apparently, when struck by engine fan blades, geese explode into large sheets of flame and continue to do so for quite a while. They also give off large smoke trails like a shot-down B-17. In the film, there is even flame coming from the bypass. Quite a thing to behold.

    In reality, aside from some compressor stall exhaust pipe flame, there shouldn't have been anything shooting out of the engines aside from—maybe—a very thin amount of smoke, and I doubt it would be visible from any distance.

  8. #48
    Senior Member TeeVee's Avatar
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    Quote Originally Posted by 3WE View Post
    An SU-35 at a similar bank and altitude might have done the same thing...
    except you're forgetting the thrust vectoring which would have negated the need for the ridiculous bank angle while permitting an VERy tight turn

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